A man in a high-visibility jacket can be heard telling commuters "it was a small fire", and Deejay Robert K, who posted the clip, said smoke was causing "chaos".

It is understood London Ambulance Service and police were at the scene and the train was evacuated at around 7.14am.

The Metropolitan Police in Hackney tweeted that there had been a "reported issue with electrics on the train in the station", but it has since been declared safe.

London Fire Brigade in Hackney said crews from Stoke Newington were called to the incident.

Duncan Cross, deputy director of London Overground, said: "At around 7.14am today there was an incident involving a faulty drill that was being carried to work by a customer at Dalston Kingsland. The train was evacuated and the emergency services attended.

"We would like to apologise to customers who were on board and to our customers whose journeys have been disrupted."